Harley Backfire Through Carb







The current symptoms are more pronounced and easier to replicate. And, when it isn’t working right, the dreaded “Bog” and the always dreaded backfire through the carburetor are effects of an accelerator pump system that isn’t equal to the task. Choosing the Right Power Valve for Your Holley Carburetor April 14, 2015 Randy Bolig Drag Race 101 , General Engine , Guest Columns , How-To and Tech Tips , Tech 5 When it comes to tuning a Holley carburetor the power valve has always seemed a mystery to many. If you can't see through them then fuel isn't going to be able to flow through it. Read: Harley-Davidson FX Model History. The thrill of riding your motorcycle is lessened somewhat if your motorcycle tends to backfire. If t he carb does no t show any gas, i t may no t have any in t he bowl. It sounds like you will need to do some troubleshooting to determine the problem and it could easily be a combination of things. 1973 - 1979 F-100 & Larger F-Series Trucks - Backfiring through carb - ive been racking my brain over this for a couple weeks now while i searched through dozens of old posts. Power valve blown out by spitback up through carb. In fact, one should expect a well-tuned high performance engine to "pop" and "crackle" when the throttle is closed at high rpm. What Makes a Car Backfire? Backfiring is the process of a spark plug, or multiple spark plugs, igniting the fuel in their cylinder out of turn, in a part of the combustion process where the exhaust valve is open on that cylinder. this carb is a direct fit for all carbureted harley and buell models from 1988 to 2006. Before I put the car away for the winter last year, it started to hesitate upon acceleration and backfire every so often through the carb. It mainly came Harley Davidson 1926-28 25/02/06, added photos on AMX12, Tillotson MS34A, Marvel and Beck carbs. Well, I don't know anything about the Super B carb, but backfiring thru the carb while trying to start it usually means I have to retard the spark a little more because it is firing before the intake valve is fully closed. Footage taken from Holley Carburetor Installation & Tuning DVD. Hey guys, I have a M-74B on my 1964 Pan and I am having some trouble getting it tuned in after taking it all apart and replacing parts. As a guest you can view the forum and photo galleries, but you have to register before you can post or view attachments. The carbs looked very clean and were easy to disassemble. Sales for 1978 topped 17,000 units, the highest in Ironhead Sportster history. Please advise me on what the real symptoms of lean vs rich system is. Gary, There is a condenser on the Onan with the electronic ignition and if it fails it can cause a lack of spark. this carb can be set up for sportsters, softails and dyna's. I'd change the secondary spring to one thats more heavy. While most of the following information applies to all CV carbs, and to some extent all carb types, this article is specific to the Keihin CVK40 found on many Kawasaki motorcycles (KLR's and Vulcans) along with some Harleys. I'd pull the bowls make sure it's all clean inside. The reason why it has been down is because last time I took it out it was backfiring through the carb really badly. Some people do not run a power valve at all, and jet up the carburetor to compensate for not having the additional fuel available at WOT that the PV would normally provide. Tuning your Harley Davidson carburetor is simpler than most think and can be performed with a few common tools. New Exhaust System = Carb Jetting? When you upgrade your bike with a new exhaust system, air box or hi-flow air filter it may upset the air to fuel ratio creating a mixture that is too rich or too lean. Mixture tuning on your Harley Davidson CV carburetor is a simple procedure that can easily be performed with basic tools. I replaced the pipes with stock pipes and it is marginally better. Read More Asked in Chevy 350 , Chevy 305 , Timing. 5k but smoothes out and has good power after that. Verify the idle is set correctly. There was no plan or idea to use mostly Screamin' Eagle parts for this project. Maybe a bad carb to intake gasket. So No real definate cause can yet be scientificly determined. The engine runs poorly at wide open throttle and backfires when backing off throttle. should have thought of that myself because it's something i know of but it just didn't come to mind. I think two well-tuned carbs will theoretically beat a single carb in respect to high-end horsepower, since each carb can be more precisely tuned to the cylinder it services, and the motor is clearly getting more air through two carbs than through one. I have a 98 Harley Heritage Custom with the 80CI EVO. Harley Davidson WL spark plugs gets black Hi, today I did a complete check in my motorcycle to verify the reason of the backfire through the carburetor. Re: Deceleration Popping explained I am glad I read this, As you can see in my signature that I have a 91 XR250R. India, US Officially Suspend Defense Cooperation. No ifs ands or buts, that's what causes it. Can't tell you what fixed it, but it seemed to fix my shotgun sound. does it idle ok? only when you hit gas does it pop? last idea. Next I'd have a look at the carburetor, take off the bowl and see if its all gummed up with crud, if so clean it. was created by syllinx22 When in park it will sometimes start sputtering and if i give it gas it will backfire through the throttle body. I have one of the old type B&S engine with carburetor that hooks to the gas tank put a rebuild in carb. A diaphragm controls the secondary carburetor port, and this is activated when a set vacuum is reached in the carburetor circuit. Removing and Rebuilding a Carburetor. Anyone have experience with this? Would adjusting the valves fix it? Could it be caused by a bad clutch one-way bearing?. The forward cylinder had a significant leak which on deceleration would suck air in causing that backfire. What can I do to fix this?. I replaced the pipes with stock pipes and it is marginally better. A back-fire or backfire is combustion or an explosion produced by a running internal combustion engine that occurs in the air intake system rather than inside the combustion chamber. The carb was backfiring and exhaust pipe. Backfiring through exhaust when starting. I would check any accelerator pump for proper operation, due to it being on acceleration only. A telltale sign of lean running is when the motor backfires through the pipes and sputters through the carb. The carbs looked very clean and were easy to disassemble. If it's backfiring outta the carb, it's generally a fuel problem. What to do?. any reference related to "harley davidson" or any harley davidson models is solely for identification purposes and is not intended to create any confusion or deception in the marketplace. it starts spitting back through the carb. When manifold vacuum increases, air is trying to come in to equalize the pressure and it will do so anywhere it can. I'd pull the bowls make sure it's all clean inside. It still backfires and it's embarrassing. Use the following suggestions to pin down your problem areas so that you can stop your motorcycle from backfiring. The number one cause of backfires through the carb is a vacuum leak. Harley Davidson Carburetor Performance Tuning Tuning Harley Davidson carburetor is simpler than most think and can be performed with a few common tools. A CV carburetor (Constant Velocity) incorporates a vacuum operated slide that varies the venturi size within the carburetor, thus maintaining a constant velocity. A few days ago, my '83 R65 backfired twice through the right carb while I was trying to start it. Re: Mercury 5 hp 4 stroke backfire through carb The small four strokes are prone to float issuestake the carb apart and get the spec on float drop and float level. and that's why harley has used it from 88-07 then going to efi. Harley-Davidson Electronic Fuel-Injection Tuning Aids D. I just had the top end rebuilt completely rings valves heads refaced etc plugs are new exhaust system is tight no leaks. Each hinge is made of 6061 T6 aluminum and machined to very close tolerances. Deceleration back-fire, rough idle, and throttle lag can be quickly adjusted by tuning your carburetor. The main reason engine backfires is because a valve is not closed when the spark plug fires. the project are from Harley-Davidson is a coincidence. Here is what happened: I started it I was on my way to work drove about 15 miles everything is fine at this point I had to to turn it to reserve as I always do (little peanut tank) I pull into the Shell station fill it up, turn the peacock back to on take off for the rest of my ride to work everything is fine for 6 miles then. The bike only wanted to run when the choke is 100%-50% open but I managed to get that down some with a carb cleaning and some idle tuning but it is still not running right and it has a hiss sound. All three of these issues have a direct effect on the air-to-fuel ratio. The Harley-Davidson engine oiling systems needs 700 RPMs or greater to deliver proper lubrication. Any easy fix?. Mild or occasional detonation can occur in almost any engine and usually causes no harm. In this instructable video, I attempted to fix a hesitation and backfiring problem on my Honda Nighthawk CB450SC using SeaFoam. An 18 mm throat splits into two small peripheral induction tracts. i believe it is from fuel making it into the exhaust because it isnt combusted fully. Please visit our support forum for post-purchase support of our products. If t he carb does no t show any gas, i t may no t have any in t he bowl. Other causes of backfire are bad or weak fuel pumps, low fuel pressure and clogged fuel filters. In addition, every hole in the carburetor body must be flushed out with carburetor cleaner and blown through with compressed air (eye protection must be worn during this procedure as fluid and/or dirt particles will be ejected from the various holes/drillings). the carb was rejetted after installing the new pipes). I always heard that if the backfire was out the exhaust it was ignition and through the carb it was valves. then started dieing out like it was starving for gas tried to adjust carb. As a guest you can view the forum and photo galleries, but you have to register before you can post or view attachments. Backfires through carb? I had the same problem with my shovel (spitting and backfired through the carb). I have seen more than one motorcycle backfire through the carb because of that--- one was a '46 knuck that burned to the ground at a gas station. 4) No power or heat source to choke. If i t ’s full of gas, t he accelera t or pump mechanism (t he gas “squir t er”) may be worn ou t. The carbs looked very clean and were easy to disassemble. We carry a full line of performance parts for leading Kawasaki Mule models, including the rugged FXT, 1140, more. Anyone have experience with this? Would adjusting the valves fix it? Could it be caused by a bad clutch one-way bearing?. True backfiring is either caused by a valve timing issue or by the ignition being so far out of proper setup that the spark plug fires when the intake valve is open and ignites the incoming air/fuel mix before the intake valve is closed. Low would cause lean, not enough fuel, backfire and shut off. Harley Davidson CV Carburetor Upgrade Harley Davidson started equipping models with the CV carburetor in 1989 and has utilized the same carb ever since. How to stop your Harley from back firing out the intake. Next I'd have a look at the carburetor, take off the bowl and see if its all gummed up with crud, if so clean it. just rebuilt a 15hp carb and sure enough per my buddy at the marine shop the plastic float arms had been attacked by Ethanol. All the parts used are readily available through your Harley-Davidson Dealer except for the spark plug wires, which can be ordered directly through Magnecor. But the bigger question is how does gas get there in the first place, and that’s a bit more complicated. Many bikes never run at the low end of the recommended 1200-1400 Idle rpm range in BMWs Manual. my quad started running like crap, it idles fine but seems to backfire through carb or something when you give it gas I cleaned carb twice, no change plug looks perfect, good color and clean fuel pump is working, clear filter is full of fuel would a bad ignition do this?. try a hot wire from the bat to the distributer to make sure it aint your harness if its poppin through the carb maybe its an intake valve stuck bent or lobe worn. However, while "at speed" or 1/3 throttle I try and accelerate (2/3 throttle) and the damn truck all but dies. Backfiring or overheating. Runs great other than the popping. Also a one-into-two rear head pipe design on a stock Harley dresser allows fresh air to be drawn up through the left hand muffler. With a carburetor, droplets of fuel can separate and puddle when the air/fuel mixture turns corners. Every model carb is slightly different, but the basic principles apply to all. Fuel burning in. Generally speaking, it may be caused by a an exhaust manifold leak. Multiple carburetor engines were also common enhancements forwith a strong tendency to explode should the engine backfire;Used on Harley Davidson. The Deceleration Pop Problem Decel Pop is many times a nasty issue to deal with. It doesn't run despite having a good spark, if I turn it over with a drill I get occasional backfiring, it is definately backfiring as the drill jerks and slows when it goes pop. Look in the lower right-hand portion of the image, this is the area of the accelerator. The Venturers Technical Support Library is for all Venture owners and brought to you as a free public service of The Venturers M/C. Harley CV Carburetor Mixture Tuning Notice: All instructions and the EZ-Just are intended for a Harley CV carburetor only. So it is somewhere in the exhaust piping, anywhere from where the exhaust leaves the engine, which is the exhaust manifold, to the exhaust pipes leading off from the manifold. It still backfires and it's embarrassing. Many bikes never run at the low end of the recommended 1200-1400 Idle rpm range in BMWs Manual. Everything is home made and DIY as usual. I first drained the fuel in the carburetor bowls. Do yourself a favor, do a compression. Something loose? I took it to both of the Harley Dealers in my area and the first told me it was the jets and charged me $500 but that did not work, then I took it to the second and they rebuilt my carb and charged me $500 and that did not work. Too much advance will cause hard starting and pre-ignition. Why does my engine backfire through the carburetor? "Backfiring" is a condition described as a loud bang, poof, explosion, etc. 05-04-09 07:30 PM - Post# 1691343 hi i got a 1963 chevy impala with a 283 engine and a 2bbl carb. The backfiring of the motorcycle is a signal that something isn't quite right. The "Bog" simply means the engine is not receiving enough fuel when you go to wide open. Please login or register. Do yourself a favor, do a compression. A few days ago, my '83 R65 backfired twice through the right carb while I was trying to start it. its not atomized well by the carb or isnt allowed to burn fully from a bad spark. it doesn't backfire now, it was a problem with a new carb and the e-clip on the needle was on the bottom notch. It will maybe be less spitting if it is not run on pressure no matter what type. Tuning your Harley Davidson carburetor is simpler than most think and can be performed with a few common tools. Multiple carburetor engines were also common enhancements forwith a strong tendency to explode should the engine backfire;Used on Harley Davidson. should have thought of that myself because it's something i know of but it just didn't come to mind. So I bought a new S&S carb for another $500 and it still backfires. Learn how to diagnose and solve an engine backfiring problem… in case it is a problem. In 1974, Harley FL Touring models switched from Bendix carburetors to Keihin, while the FX models continued using the Bendix carb. But there may be other things going on too - have you checked for the evil manifold leak???. I have seen more than one motorcycle backfire through the carb because of that--- one was a '46 knuck that burned to the ground at a gas station. Anyone have experience with this? Would adjusting the valves fix it? Could it be caused by a bad clutch one-way bearing?. Backfires Through CarburetorThis is. Completely random backfire through throttle body. For you 6 volt Packard owners the Airtex Fuel Pump Model E8011 is a good 6 volt draw through pump. Blip the throttle a couple of times and observe the results. Shop the best 1999 Harley-Davidson Softail Heritage Classic FLSTC Carburetor for your motorcycle at J&P Cycles. Update: the false panic and stampede in Times Square was not caused by a Harley backfiring. Use a new intake to carb gasket. In my how-to video I will walk you through the basic principles and fundamentals of what you are adjusting and how it will impact your bike's response. Any setting help is good,bike has been back and forward to bike shop for popping/backfiring on deceleration,just cant get rid of it. When in doubt consult your factory service manual and/or a professional motorcycle technician. The Deceleration Pop Problem Decel Pop is many times a nasty issue to deal with. I have a 1969 Chrysler Marine 318 with a Carter AFB carburetor in a '69 Correct Craft Barracuda. Is your 2-stroke BACKFIRING? This could help Over the last month or so while everyone is getting their carts dialed in for the season, I have noticed an above-average number of posts asking about backfiring issues with Marathons, so I thought I'd throw this post together so there's a searchable solution for those with questions. But prolonged or heavy detonation can be very damaging. our 20HP kohler does the same thing if you dont let it idle for a minute. If backfiring occurs through the carburetor then adjust the idle mixture screw out another 1/8 turn. It could be a number of things as described in previous. Im experiencing a problem where it backfires only when it hits a certain rpm, but only in idle. Backfires Through CarburetorThis is the main reason why modified Harley engines tend to backfire through the carburetor more frequently than stock engines. Tried several times same result, runs strong if I feather the rpm's between 1400-2200 rpm's but as soon as you head towards idle it'll backfire. But the bigger question is how does gas get there in the first place, and that's a bit more complicated. The 1978 Electra-Glide was the first Big-Twin Harley to have electronic ignition. The thrill of riding your motorcycle is lessened somewhat if your motorcycle tends to backfire. A CV carburetor (Constant Velocity) incorporates a vacuum operated slide that varies the venturi size within the carburetor, thus maintaining a constant velocity. If backfiring occurs through the carburetor then adjust the idle mixture screw out another 1/8 turn. comA backfire that you hear in your tail pipe isA backfire back out through your intake. ·Forums > Harley-Davidson Sportster: Carb poppingthrough the carb canis not a Sportster thing to backfire through the Carb although they. If i t ’s full of gas, t he accelera t or pump mechanism (t he gas “squir t er”) may be worn ou t. If you can see through the jet it isn’t clogged. It could be a number of things as described in previous. What causes a motor to spit through the carb? 1 Welcome, Guest. Low would cause lean, not enough fuel, backfire and shut off. Backfires ThroughBig Twin & SportsterThis is the main reason why modified Harley engines tend to backfire through the carburetor more frequently. 05-04-09 07:30 PM - Post# 1691343 hi i got a 1963 chevy impala with a 283 engine and a 2bbl carb. How to Make a Car Backfire. Can The backfiring Be Minimized Or Eliminated? Published by Cyril Huze April 14th, 2016 in Customs, Editorial and Exhaust. 2002 Kawasaki Prairie 650 - Carb Help Mechanic told me that was normal for Kawasaki to spit back through carb at certain RPM. I believe this bike has a points type ignition. Went out and finally managed to get my exhaust fitted to my downpipes using a gasket I made from a can of Macaroni Cheese Anyway, tried to start my bike after it and it wouldn't start, it was turning over but just wouldn't fire up, then it sounded like it was backfiring Battery got drained so I just fully charged it and same is happening - turning over but not firing up!. Use 64panhead's sequence, EXCEPT be sure to turn the choke OFF before kicking it with the ignition ON. Backfire thru the Carb Model A (1928-31) backfiring through the carb or popping with the timing retarded can be attributed to a lean mixture. The bike is also missing and backfiring below 3. This simple procedure is a great Harley tech tip that applies to all Harley carbs from 1989 to present that use the CV style Harley Davidson carburetor. What's it mean when a bike "backfires" through the carb? A little repair work and so far it is lookin really good. This is called a Venturi. Removing and Rebuilding a Carburetor. Use the following suggestions to pin down your problem areas so that you can stop your motorcycle from backfiring. Well, I don't know anything about the Super B carb, but backfiring thru the carb while trying to start it usually means I have to retard the spark a little more because it is firing before the intake valve is fully closed. All exhaust popping or backfiring on a Harley-Davidson motorcycle is caused by fuel combustion in the exhaust manifold or the header pipes. Really pulling the carb apart and spraying the jets and all the passages out and inspecting it sounds like what needs to be done. Carburetors are calibrated at 70° at sea level. The acceleration backfire is coming from the carb and rarely is heard in the pipes. In this video we tackle the rebuild process from the carburetor cleaning to a few modifications and especially the float adjustment of a Harley Davidson CV carburetor utilizing a standard rebuild kit. The thrill of riding your motorcycle is lessened somewhat if your motorcycle tends to backfire. was created by syllinx22 When in park it will sometimes start sputtering and if i give it gas it will backfire through the throttle body. But I guess we can add fouled plugs to the list of things that can cause backfire on acceleration. 1979 Sportster. Why does my 2003 Fatboy cough and backfire through the carb? It only does it every so often. when idling the engine down, or after the engine has been shut off. Backfiring during acceleration can also be caused by internal carburetor problems, low compression, leaks in the fuel tank, lean engine conditions, and weak or broken valve springs. The Deceleration Pop Problem Decel Pop is many times a nasty issue to deal with. its not atomized well by the carb or isnt allowed to burn fully from a bad spark. Tuning your Harley Davidson carburetor is simpler than most think and can be performed with a few common tools. Also, since there is no spark advance cable, what is holding the timer in full advance?. thinking this fixed the problem i began to drive her again, only to find she is still backfiring a lot and im noticing a popping/clicking noise around. If they dynoed it and now you ask to get a remap to rid yourself of the popping you may be looking at some situations where you are running lean at cruising speeds. Low would cause lean, not enough fuel, backfire and shut off. Does your stock Harley cough and spit through the carb, especially when you pull away from a traffic light?. Re: What makes an engine backfire through the carb I am not expert with carbs and hopefully some of the Jeep gods on this board will be able to shed some light on it for you. Had a somewhat similar situation with one of my Crusader 350's backfiring out the exhaust- it was the ditributor cap. It sounds like you will need to do some troubleshooting to determine the problem and it could easily be a combination of things. open the GAV some and see if that helps any. Mixture tuning on your Harley Davidson CV carburetor is a simple procedure that can easily be performed with basic tools. · Motorcycle Message Board - Motorcycle USA > MotorcycleUSA. Backfire through intake/carb. A carburetor backfire describes the small explosion that sometimes occurs when starting up a car. through the carburetor or throttle body. POOR RUNNING QUALITY DOES NOT MEAN A DEFECT IN THE CARBURETOR. In my how-to video I will walk you through the basic principles and fundamentals of what you are adjusting and how it will impact your bike’s response. In fact, one should expect a well-tuned high performance engine to "pop" and "crackle" when the throttle is closed at high rpm. Anytime you rejet or change exhaust or air cleaner intake it is suggested to adjust the mixture. If backfiring occurs through the carburetor then adjust the idle mixture screw out another 1/8 to 1/4 turn. is it engine temp sensor, bad coil, throttle position sensor, or worse!. I only taking a guess here. Proponents of this school usually argue that the power valve is prone to failure after a backfire through the carb. Read More Asked in Chevy 350 , Chevy 305 , Timing. But since most of those guys are out wheeling while im stuck in my office today, see if this helps. The needed adjustment to remedy golf cart backfiring will vary between manufacturers and year models. So you have a nifty Weber DCOE or S&K Racing sidedraft carb, set up for your vehicle, you're ready to chew gum and kick butt, and you've run out of gum. Backfire, through the carb means LEAN. The "Bog" simply means the engine is not receiving enough fuel when you go to wide open. The backfiring of the motorcycle is a signal that something isn't quite right. Do yourself a favor, do a compression. The number one cause of backfires through the carb is a vacuum leak. The accelerator cable may move through the plate, but the plate itself cannot move prior to the micro switch click. If the engine is flat or will not accelerate, decrease the main jet by. Open mufflers: "Gutted" mufflers with stock (or stock-like) header pipes tend to perform poorly in the same rpm range as straight pipes and exhibit similar symptoms. Inside a carburetor is a venturi, fig 1. The shifter control arm and shaft has come off my harley davidson road king twice with only 12,000 miles. Blip the throttle a couple of times and observe the results. This has continued through 100 miles of riding. The filter is washable but doesn't hold up too well when you happen to backfire through the carburetor why trying to fine tune or whatever. My mechanic says the carb needs a rebuild but says he does not have time for it. It's going very, very well on the road and idling, throttle response, power, etc is great. How to Make a Car Backfire. Removing t he t op screws on t he carb body will reveal t he floa t chamber and floa t assembly. It starts really easily but does not get to full speed (there is no idle setting). AN ADVANTAGE OF THE WEBER CARBURETOR IS ITS EASE OF ADJUSTMENT AND TUNING. com/deceleration-backfire-tuning-your-carb/ on adjus. The first DT model, the DT-1, was released in 1968 and quickly sold through its initial 12,000 production run. Idle adjustment should not be a problem on your Harley’s carb. Blip the throttle a couple of times and observe the results. A carburetor backfire describes the small explosion that sometimes occurs when starting up a car. the fact is the harley 40 mm cv is one of the best [high performance] carbs made. If it is just popping on decel then you just have fuel that is being pushed through and not ignited. •Always use an insulator block between carb and manifold. On the TK carbs, though, each carb has an actuator, but it appears that there is one primary enrichment circuit control on carb 3. The intake side also needs scrutiny; even if there have been no modifications. Is it running rich or lean? Missing?. The carburetor must be clean, as fuel cannot flow properly through a dirty carburetor. The pilot jets seem to be OK, I can see daylight and blow through them easily. Generally speaking, it may be caused by a an exhaust manifold leak. Before I put the car away for the winter last year, it started to hesitate upon acceleration and backfire every so often through the carb. Not just a little, anything over 1/2 throtle it would pop several times and bog back down. The thrill of riding your motorcycle is lessened somewhat if your motorcycle tends to backfire. Fuel can not flow properly through a dirty carburetor; this will cause a lean-running engine. The needed adjustment to remedy golf cart backfiring will vary between manufacturers and year models. BUSHMAN'S CARB TUNING SECRETS. But there may be other things going on too - have you checked for the evil manifold leak???. My 86 TRX250 is backfiring through the carb at low idle. 01' Sportster idle problem/exhaust backfire, please help me out! Hi guys new Harley owner here. All the parts used are readily available through your Harley-Davidson Dealer except for the spark plug wires, which can be ordered directly through Magnecor. If i t ’s full of gas, t he accelera t or pump mechanism (t he gas “squir t er”) may be worn ou t. 2016 Harley Davidson Softail Breakout FXSB Parts & Accessories at CycleGear. There could be a little gunk built up around the edges so spray them down with carb cleaner and let them sit a bit. The most common culprit is usually something wrong with the ignition system. Troubleshooting - backfire through carburetor. All of these, the exhaust, air cleaner, ignition, cams, etc. Was that a backfire or a gunshot? Either way, it looked like more than a flesh wound that Harley-Davidson (NYSE: HOG) suffered Friday, in the wake of earnings numbers suggesting that this company. Dominate the dragstrip with gasoline- or alcohol-compatible carburetors. Harley CV Carburetor reference diagram. Harley Davidson WL spark plugs gets black Hi, today I did a complete check in my motorcycle to verify the reason of the backfire through the carburetor. 2004 HARLEY DAVIDSON SOFTAIL Service Repair Workshop Manual provides step-by-step. Owned Lots of Sportsters and is not a Sportster thing to backfire through the Carb although they will do it if the Carb ain't right. This easy method is a excellent Harley tech tip that applies to all Harley designs from 1989 to 2006 that use the CV (frequent velocity) fashion carburetor. ↳ 1929 Harley-Davidson Inspected & Approved Accessories. To do this insert an iron bar into the exhaust pipe and then hit it several times with a. In fact, single fire ignitions can generally eliminate backfiring in any Harley. Some very open or incorrectly designed exhaust systems encourage backfiring. There can be several reasons for this. Welcome to Harley Chat Group. The are more than a few reasons for backfire when starting a bike utilizing a Linkert carburetor as Cotton has mentioned a few. Re-mapping should help fix it. Proponents of this school usually argue that the power valve is prone to failure after a backfire through the carb. You bolted on the carb in place of your SUs or Zenith-Stromberg and voila! You have worse gas mileage, and the power gain is slight enough to be psychological. a two cable throttle system designed for use with the stock constant velocity (CV) type carburetor. When I first bought the bike, it had a Vance and Hines exhaust on it. I fixed the exhaust leak, swapped to a smaller intermediate jet in the carb, lowered the idle and changed plugs and wires. or it is just running lean and has excess fuel that keeps vaporizing. 3) Replace the power valve. was created by syllinx22 When in park it will sometimes start sputtering and if i give it gas it will backfire through the throttle body. A diaphragm controls the secondary carburetor port, and this is activated when a set vacuum is reached in the carburetor circuit. I can wait it out or floor it and it will stop. Its purpose is oh so simple and its function is oh so critical. Footage taken from Holley Carburetor Installation & Tuning DVD. Now the bike is only 4 years old but I do have 99k on the motor. If you just have mild backfiring, you can try this. make sure there is no crusting on the cap and rotor if so scrape it off this includes the spark triggger points on the cap itself. I backfires through the carb under light acceleration or when cruising, fine under hard acceleration. I have a 98 Harley Heritage Custom with the 80CI EVO. Carburetor Troubleshooting Guide. Real backfiring means the engine is not properly timed and the fuel/air mix is getting a spark and ignition at the wrong time (when the intake valve is open). ·Forums > Harley-Davidson Sportster: Carb poppingthrough the carb canis not a Sportster thing to backfire through the Carb although they. Sprayed carb cleaner while running to check for vacuum leaks on both intake and carb boots. backfiring with flame through throttle body was created by highlander Hello to all Any help, would be greatly appreciated, let me start by starting at the beginning. Its a tillotson #HR74A. Out of the box jetting should be close for most applications.